Bose Condensates and Fermi Gases at Zero Temperature

We consider the $T=0\mathrm{}$ ground state of mixtures of bosons and fermions. Applying the Thomas-Fermi approximation we show that, depending on the strength of boson-boson and boson-fermion interactions, the Fermi gas may constitute a “shell” around or a “core” inside the Bose condensate, or even both.